Date post: | 24-Jun-2015 |
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Education |
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Let’s go to the ballet
0See if you can accurately name all the shapes
Polyhedrons Polyhedrons
Pyramids PrismsPyramids Prisms
Lesson Objectives
0To understand the differences between platonic solids, prisms and pyramids
0To examine the properties of polyhedrons0To develop your own NET shapes using 3D shapes
provided
Polyhedrons
0Poly = Greek for many0Hedron = Greek for face
0Polyhedron = Many Faces!!
Likely Difficulties
0Names for 2D figures and 3D objects often get confused because the beginning of names are similar…
0Dodecagon = 12 sided 2D shape0Dodecahedron = 3D 12 sided regular pentagon
3D Shape Properties
Platonic Polyhedrons
0 Plato, a Greek philosopher and mathematician.
0Worked out that some polyhedrons are identical in shape and size.
0Edges = Same length0Angles = Same size0 Vertices = Identical
What does that mean?
Platonic Polyhedrons are Perfect!
0All vertices are surrounded by the same plane shape. 0Any face can be the base.0They are beautifully symmetrical.0Only five of them exist!
Platonic Solid
Picture Number of Faces
Shape of Faces
Number of Faces at Each Vertex
Number of
Vertices
Number of Edges
Unfolded Polyhedron (Net)
Tetrahedron
4 Equilateral
Triangle (3-sided)
3 4 6
Cube
6 Square
(4-sided) 3 8 12
Octahedron
8 Equilateral
Triangle (3-sided)
4 6 12
Dodecahedron
12 Regular
Pentagon (5-sided)
3 20 30
Icosahedron
20 Equilateral
Triangle (3-sided)
5 12 30
Pyramids & Prisms0Prisms have two identical, parallel faces joined to one
another by rectangles. Examples are;
Pyramids & Prisms
0 Pyramids have one face with at least 3 edges, the faces meeting these edges are ALL triangles.
0 NOTE: Pyramids get their name from the shape of their base
0 There are many more pyramids than these ones shown
Other 3D shapes
Activity!
0You will be given some examples of 3D shapes0Name the shapes you have been given0With your elbow partner, use the graph paper
provided to draw a NET of the shapes you have been given
0Cut out the Nets you have drawn and see if they can be made into the original 3D shapes (you might want to leave a lip on some sides so you can glue it together)
0Did you get it right? If not, what do you need to change to make it correct?